The present invention relates to a laminating technique and, in particular, to a technique that is effectively applied to a laminator of the type that cuts a continuous thin film to a predetermined size and laminates it over a substrate.
Printed circuit boards used in electronic equipment such as computers are formed by depositing a predetermined pattern of wires of conductive materials such as copper on one or both sides of an insulating substrate.
Printed circuit boards of this type can be manufactured by the following process: first, an assembly of a photosensitive resin layer (i.e., photoresist) and a protective transparent resin film is laminated over an electroconductive layer on the insulating substrate by thermocompression, and this step is commercially carried out with a device called a "laminator"; a film with a wiring pattern is then superposed on the assembly and the photosensitive resin layer is exposed to light for a predetermined period of time through the patterned film and the transparent resin film; subsequently, the transparent resin film is stripped with a peeler and the exposed photosensitive resin layer is developed to form a mask pattern for etching; thereafter, the unwanted areas of the conductive layer are etched away and any residual photosensitive layer is removed to produce a printed circuit board having a predetermined wiring pattern.
The above-described process of manufacturing a printed circuit board necessarily involves the step of automatically laminating an assembly of a photoresist and a protective film over the conductive layer on the insulating substrate by thermocompression with a laminator. This step of thermocompression lamination generally proceeds as follows.
First, a continuous sheet of assembly that has been wound on the feed roller in the laminator is supplied to the substrate by means of a main vacuum plate. The surface of the main vacuum plate over which the assembly is supplied is provided with a plurality of suction holes through which the assembly is sucked onto the main vacuum plate as it is supplied to the substrate. The leading edge of the assembly being supplied to the substrate is temporarily bonded (by thermocompression) onto the conductive layer on the insulating substrate by means of a temporary bonding portion provided at the downstream end of the main vacuum plate. In order to enable the supply and temporary bonding of the assembly, the main vacuum plate is mounted on the laminator body via a support member that is movable toward or away from the substrate.
In the next step, the assembly with its leading edge bonded temporarily to the substrate is laminated over said substrate by means of a thermocompression roller. When a given amount of the assembly has been laminated over the substrate, it is cut with a cutting unit to a predetermined size corresponding to the substrate. The cutting unit is mounted on the support member together with the main vacuum plate.
Since the main vacuum plate and the cutting unit, each of which is a heavy-duty component, are mounted on the same support member, the prior art laminator has suffered from the disadvantage that a drive source (e.g. air cylinder) having a large capacity (driving capability) must be used to effect displacement of the support member.
Also, in the prior art, in the delivery path of the thin film bonding apparatus, since the thermocompression rollers are moved, a substantial space is formed between the thermocompression rollers and the delivery rollers for delivering the substrate over which the thin films are laminated. Accordingly, in particular in case of delivery of a thin substrate, a leading end of the substrate is liable to be suspended downwardly before the delivery rollers. As a result, it is difficult or impossible to lead the substrate to the delivery rollers.
These and other problems to be solved by the present invention and the novel features thereof will become apparent by reading the following description in this specification in conjunction with the accompanying drawings.